1. Field of the Invention
The present invention relates to a display device. Particularly the invention relates to a display device equipped with a touch sensor over a display area where an organic EL element is formed.
2. Description of the Related Art
It is demanded that a display device for a mobile device should be reduced in thickness and weight. In view of this, when a liquid crystal display device and an organic EL display device are compared, the organic EL display device is considered more advantageous in that it needs no backlight. Also, as the development of techniques for forming a pixel drive circuit and an organic EL element on a flexible substrate has been underway, a thinner and lighter display than a conventional display using a glass substrate has been realized. In this course of events, a reduction in thickness of members other than the display device, such as the touch sensor and the polarizer, is demanded as well. Particularly, the thickness increases if the touch sensor is bonded and mounted on the display device as a separate member. Therefore, a touch sensor as a built-in member of the display device is demanded.
A method for providing a built-in touch sensor in the organic EL display device is disclosed in Japanese Patent No. 5,778,961. According to this invention, it is disclosed that one of the electrodes forming the organic EL element is formed in the shape of a band and used as an electrode of the touch sensor.